Abstract |
The selectivity of moxisylyte and its two metabolites deacetylmoxisylyte and demethyldeacetylmoxisylyte, for alpha 1- and alpha 2-adrenoceptors has been investigated in the pithed rat. Alpha 2-adrenoceptor blockade was measured by antagonism of the inhibitory effect of clonidine on the tachycardia produced by electrical stimulation of the cardiac accelerator nerves and of the pressor response to B-HT 933. alpha 1-Adrenoceptor blockade was measured by inhibition of the pressor response to (-) phenylephrine and to stimulation of the sympathetic outflow from the spinal cord. The three drugs (5 X 10(-6) to 2 X 10(-5) mol/kg i.v.) did not affect the inhibitory effect of clonidine and were equipotent as antagonists of the pressor response to B-HT 933, but only at the higher dose (10(-5) mol/kg). Moxisylyte and its metabolites (2.5 X 10(-6) to 10(-5) mol/kg i.v.) reduced the pressor response to (-) phenylephrine and to stimulation of the sympathetic outflow of the spinal cord in a dose-dependent manner. They were much more effective against (-) phenylephrine than B-HT 933. These results indicate that the three drugs are preferential alpha 1-adrenoceptor antagonists in vivo.
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Authors | J Roquebert, A Malek, M H Creuzet, F Cognie, H Pontagnier |
Journal | Archives internationales de pharmacodynamie et de therapie
(Arch Int Pharmacodyn Ther)
Vol. 266
Issue 2
Pg. 282-93
(Dec 1983)
ISSN: 0003-9780 [Print] Belgium |
PMID | 6320755
(Publication Type: Journal Article)
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Chemical References |
- Azepines
- Receptors, Adrenergic, alpha
- Phenylephrine
- deacetylmoxisylyte
- demethyldeacetylmoxisylyte
- azepexole
- Clonidine
- Moxisylyte
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Topics |
- Animals
- Azepines
(pharmacology)
- Blood Pressure
(drug effects)
- Clonidine
(pharmacology)
- Electric Stimulation
- Heart Rate
(drug effects)
- Male
- Moxisylyte
(analogs & derivatives, pharmacology)
- Phenylephrine
(pharmacology)
- Rats
- Rats, Inbred Strains
- Receptors, Adrenergic, alpha
(drug effects)
- Spinal Cord
(physiology)
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